ISLAMABAD, Pakistan (CNN) -- Pakistan's military continued its assault Thursday on militants in Taliban-held areas, its chief spokesman told reporters.

Pakistani army trucks move military equipment into the troubled Buner district Thursday.

So far, 14 militants have been killed in the past 24 hours, Maj. Gen. Athar Abbas said. The operation is still ongoing in the districts of Dir and Buner, which was recently seized by the Taliban in violation of an agreement with Pakistan's government.

Pakistani forces have completely secured Daggar, the main town in Buner and the scene of heavy fighting on Wednesday, Abbas said.

The Daggar operation resulted in the deaths of 50 militants, but freed 18 Frontier Corps personnel who had been abducted by militants, he said. Fifty-two of their colleagues are still believed to be held by their suspected Taliban kidnappers.

This week's military operation has resulted in more than 180 militant casualties since Sunday, while the military has suffered one death and one injury, according to Abbas. He said he hopes the operation will be completed by the end of the week.

Pakistan has asked the United States to supply its forces with helicopters, communication equipment and night vision technology, Abbas said Thursday.

Most of this week's casualties happened on Tuesday, when Pakistani fighter jets launched airstrikes, killing at least 70 militants in the Dir district, according to the Pakistani military.

The operation is part of the Pakistani army's intensified drive against the Taliban in its restive tribal regions. The Pakistani government has been criticized for not cracking down on militants along its border with Afghanistan. As a result, the U.S. military has carried out airstrikes against militant targets in Pakistan, which have rankled relations between the two countries.

The military campaign has apparently not stopped Washington from carrying out unmanned drone attacks on Pakistan's soil. A suspected unmanned aerial vehicle killed six people Wednesday night in the village of Kaniguran in the tribal district of South Waziristan near the border with Afghanistan, Pakistani intelligence sources said.

Pakistan has complained repeatedly about what it says are American airstrikes on its territory. The U.S. military in Afghanistan has not commented on the strikes, which typically target Taliban fighters in the border region. But the United States is the only country operating in the region known to have the capability to launch missiles from remote-controlled drones.

U.S. President Barack Obama is "gravely concerned about the situation in Pakistan," he told reporters Wednesday night.

Speaking at a news conference capping his 100th day in office, Obama said the United States has "huge national security interests in making sure that Pakistan is stable" and doesn't end up a "nuclear-armed militant state." But he stressed he was more concerned about the ability of Pakistan's civilian government to "deliver basic services," and not "that they're immediately going to be overrun" by the Taliban.

Pakistan's recent military crackdown has led to an exodus of civilians from the region. At least 33,000 residents have left their homes in the midst of the recent fighting, according to Amnesty International.

Civilians fleeing from Lower Dir in Pakistan's North West Frontier Province join more than 500,000 people already displaced by the fighting, the U.N. High Commissioner for Refugees said.

The Pakistani military completed its operation to eliminate and expel militants in Dir Tuesday, and is now focusing on the Buner district, Abbas said. About 300 militants entered Buner a few days ago, in violation of the Taliban's recent agreement to leave the district, he said.

Buner is about 60 miles from Islamabad, but Abbas said the militants pose no threat of entering the capital. The fighter jets pounded targets in Buner and the Swat Valley in an effort to block the militants' entry and exit points, according to Abbas.